Birds on Gough Island in the South Atlantic are being threatened by an invasive population of mice. Not just any mice though, as the Guardian reports…

What is horrifying ornithgologists [sic] is that the humble house mouse which landed on Gough has somehow evolved to two or even three times the size of an ordinary British house mice [sic2], and instead of being a vegetarian, eating insects and seeds, has adapted itself to become a carnivore, eating albatross, petrel and shearwater chicks alive in their nests. They are now believed to be the largest mice found anywhere in the world.

The mice, which sometimes attack bird nests in groups, are completely out of control, the paper warns. This story first surfaced in 2005 but it has been given added legs now that two birds from the island, the Tristan albatross and the Gough Bunting, have been listed as critically endangered on the IUCN’s Red List

“In the presence of house mice, the albatross and the bunting have no chance of survival,” says Geoff Hilton of the Royal Society for the Protection of Birds (press release). “Things are getting worse and the only hope for these threatened birds is complete eradication of the mice.”

To this end, the RSPB wants thousands of tonnes of mouse poison dropped on the island by helicopter. The Daily Telegraph says this could cost £2.6 million.

The problem of the Gough mice surfaced last year in the journal Biology Letters, where Ross Wanless and colleagues noted:

The house mouse, Mus musculus, is one of the most widespread and well-studied invasive mammals on islands. It was thought to pose little risk to seabirds, but video evidence from Gough Island, South Atlantic Ocean shows house mice killing chicks of two IUCN-listed seabird species.

…

Mice visited every filmed burrow, and attacked and killed one of the three great shearwater chicks and six out of nine Atlantic petrel chicks. No chicks displayed appropriate behavioural responses to attacks, even though mice had eaten through the body wall of one filmed albatross chick and were consuming the contents of the chick’s abdominal cavity.

The picture footage from that paper, which is reused in today’s coverage, is quite nasty. The video is worse. The adult albatross only responds at all when a mouse takes a nip at its eye. It’s freakin’ eye! Seriously, the video is quite horrible, and not in an entertaining George Romero kind of way.

In other Red List news, 1,226 birds are now considered threatened (press release). Of 26 species that changed category, the situation has got worse for 24 of them (full list of changes).